By Jean-Jacques Segalen (jjacques) September 6, 2009
Vines are an important part of tropical flora hence we do have quite a few of those on the island, some are endemics, some are indigenous and many are exotic, we will today enjoy a small sample, to be followed by other articles as the subject is pretty vast!
We start with an indigenous vine, Strongylodon siderospermus. We might as well explain what the term indigenous means when applied to a plant...it simply means that the plant is considered native to the area. In some cases, the plant originally came from another place but was introduced long ago and is now considered part of the local flora. Indeed, Strongylodon siderospermus originates from a vast area comprising the lowlands of Eastern Indian Ocean and the Western shores of Pacific Ocean, it can be found also in Madagascar. Known as ‘cadoque blanche' on Reunion, it is only found in rain forests of the southern parts of the island, climbing up trees to bloom. Part of the former Leguminosae family (now the subfamily Papillionaceae), the Strongylodon genus comprises some 20 species, amongst which the fabulous S. macrobotrys or jade vine from Philippines. Our local species can grow to 10 meters long and produces nice pendulous clusters of red to orange red flowers which will transform into papery pods filled with one to two seeds. Those seeds are black and rounded with a prominent hilum and are very hard, hence the species name as ‘sidero' means iron and ‘spermus' means seed, locals sometimes would carry two of them in the pocket to prevent or cure backache and though there is no scientific evidence of its efficiency I quite often carry some as preventive action...
Next is a showy species that is a common sight in ravines of the West coast and is much better enjoyed at some distance! Caesalpinia decapetala, (synonym of C. sepiaria and Reichardia decapetala ), a member of the Caesalpinaceae subfamily comes from tropical Asia. It was introduced to make defensive hedges and has since then escaped in the wild where it has become a nasty invader. And defensive it is! Spines and curved thorns are scattered all over the whole plant, the tips oriented into different directions will securely cling to clothes and skins unaware of the trouble...The 'sappan', 'liane sappan' or 'Mysore Thorn' in nearby Mauritius island can grow to 15 meters (45 feet) long and produce pretty thick stems armed with large prickles. Though nasty, it ertainly has decorative qualities. When blooming has it bears long clusters of bright yellow flowers arranged as racemes. Eating the seeds is recorded in ancient China as bringing visions of ghosts and demons which does really makes the plant a not very welcomes neighbor.
Now let us leave the dry hot ravine beds for some cool air and bright green plants as the following vine grows between 1000 and 2000 meters (3,000 to 6,000 feet) high like Plaine des Caffres. Passiflora tarminianavar. mollissima was imported some fifteen years ago by local fruit development program but did not impress Creole palates and is nowadays seldom found except in private gardens here and there, at the right elevation. The ‘grenadille banane' known by a large numbers of names in its native South American countries of Venezuela, Colombia, Peru and Bolivia such as ‘taxo', ‘curuba', ‘tumbo' produces delicious pink pendulous flowers followed by elongated fruits the size and shape of a small ripe banana. The soft downy skin protects a very large number of seeds encased in the orange flesh and which is best when turned in juices, eating them out of hands like is done for most passion fruits ends in discarding them, the crushed seeds having a bitter taste in the mouth. Now, though this plant displays wonderfully colored flowers and tasty fruits it has a dark side as it may turn into a fast spreading weed like in Hawaii where it has colonized parts of some island with the help of wild pigs. Those animals eat the fruits and discard seeds in places where man can hardly get, to the point that some endemic species are threatened, the vines coveringand suffocating bushes and small trees.
A real wonder and a quite rare sight on the island, this one has only made it so far to very few collector's gardens, you know the kind of place owned by crazy cyber-gardeners who not only collect unusual species but write about them on the Net...Tecomanthe dendrophila (also known as T. venusta ) is one of the five or so species of the genus, member of the Bignonaceae family, famous for its trumpet-shaped corollas.It grows wild in the Moluccas, New Guinea and Solomon Islands, the sort of place where few people go shopping for plants, fully equatorial and where there are still some of the very last virgin forests. All members of the genus are woody twining climbers, hence solid lianas and this one will happily grow to fifteen meters (fifty feet) long, producing stunning made of dense clusters of long dark pink lobes with a lighter shade in the throat. Those amazing blooms only comes on second year growth so you will need some patience but this will be highly rewarding, it requires fertile and loose soil, full sun to partly shaded exposure. The last good news about it is that you can propagate it very easily from cuttings so once you have one plant in the garden you know you also have a valuable source for trading!
Another quite showy one. We now admire the bright orange glow of the well-named ‘flame-vine', another member of the former Leguminosae family (now Bignoniaceae subfamily), the Pyrostegia genus only comprises three or four species all from tropical South America. Pyrostegia venusta (= P. ignea ) originates in Southern Brazil, northern Argentina, Paraguay and Bolivia. Again, a woody climber which may reach 30 meters (100 feet) long!It will benefit from a seasonally dry climate and well drained soils, flowering in the tropics is at the end of winter and can be pretty impressive with bright orange flowers held in dense terminal clusters. The leaves have three leaflets with one transformed in a tendril to help the plant cling strongly to any available support. This one is also easy to propagate through cuttings, stems in contact with the ground may produce roots naturally.
We will keep enjoying colorful corollas, the ones coming now are pink as stated by the Latin name: Asarina erubescens (also called Lophospermum erubescens ) which belongs to the Scrophulariaceae family like the foxglove and does produce a quite similar flower, displaying also hairs on the inner and outer parts of the long corolla. It comes from Mexico and will grow fine in rocky soils and in full sun. The triangular shaped leaves are decorative by themselves and the plants uses the curves petioles to grab and hold what is around. The flowers turn into papery round seed pods which are full of tiny winged seeds ready to fly away. It is a perennial but can be grown as annual in temperate areas as it produces flowers quite fast from seedling. Though pink is the usual color for this species there is also a cultivar with pure white flowers, growing the two plants in the same place gives the impression of having a two-colored vine.
So we only saw six of those fascinating plants that creep, climb and slowly but surely can cover an ugly fence or uninteresting decaying plant, we still have many more to discover, so be sure to come back!
About Jean-Jacques Segalen
I am a Parisian born professional horticulturist specialized in tropical seeds producing, living on Reunion island (just between Mauritius and Madagascar) since 20 years . I spend a lot of time gathering seeds in the wild, the ones I do not grow that is. Also a dedicated Tai-Chi practitioner and fully certified arborist-tree surgeon
Just released my first book on tropical plants and fruits, check it at http://www.barbadine.com/pages/livrejjGB.html